2 the shortest introduction

plate_f1.m, plot_n.m

draw n-th eigenfunction (n=4 ... the lowest positive eigenvalue)

>> N=160
>> mu=0.3
>> a=plate_f1(N,mu);
>> [v,d]=eigs(a,200,0);

>> format long g
>> sort(diag(d))
ans =

      2.62483490092012e-07
      3.23730085560577e-07
      3.97631977037723e-07
          181.367464056553
          383.879231655339
          588.857298220385
           1210.6936945447
          1210.69369457591
          3729.71656195089
            3729.716561981
   (後略)

>> n=4
>> plot_n(v(:,201-n),N,N)

図 1: the fourth eigenfunction $\varphi _4$

図 2: the fifth eigenfunction $\varphi _5$